The present invention relates to a charge trap type non-volatile memory device and a program method thereof.
Non-volatile memory devices for storing data can be classified into a floating gate type non-volatile memory device and a charge trap type non-volatile memory device, depending on the type of storage layer that comprises a unit cell of a memory cell. The floating gate type non-volatile memory device is adapted to store charges in a floating gate, whereas the charge trap type non-volatile memory device is adapted to accumulate charges on a trap existing in a dielectric layer, such as a silicon nitride layer. The floating gate type non-volatile memory device requires a high voltage for program and erase operations when the cell size is reduced. In contrast, the charge trap type non-volatile memory device complies with low power and low voltage requirements and can realize high integration.
In the charge trap type non-volatile memory device, charges of several energy levels are trapped at a specific memory cell due to the distribution characteristic of trap energy. In particular, shallow trapped charges of energy distributions of trapped charges easily disappear even at a low electric field such as a read voltage, thereby degrading read endurance.